The present invention relates generally to actuation devices and more particularly to marine accessories, such as a vessel fender. A vessel or boat fender may be used by vessel operators or dock workers in an attempt to protect their boat from contacting a dock, pier, seawall or other such structure during docking and/or mooring.
While available in a variety of different sizes, shapes and designs, a typical prior marine fender included an air-filled, substantially cylindrical device that may be placed at various locations along a vessel port or starboard side to protect from direct contact with a dock, pier or seawall, for example, to which a boat is or is to be secured. Multiple fenders may be used at port and/or starboard sides with a typical application including at least one fender at the bow (fore) area and one fender at the stern (aft) area at the port and/or starboard sides of the boat. In some applications, boaters may use additional fenders that may be placed, strategically, along the port or starboard (or fore or aft) sides of the boat.
A marine fender absorbs the kinetic energy of a boat or vessel berthing or otherwise being forced against a jetty, dock, pier, seawall or other vessel (hereafter referred to as a dock), for example. Fenders may be used on all types of personal and commercial vessels, from cargo ships, ferries, barges, to fishing and sailing vessels, personal watercraft and yachts. Fenders are used to prevent or minimize damage to vessels and berthing structures. To do this, fenders preferably have high energy absorption and low reaction force. In other words, marine fender systems are preferably not substantially underdamped, and are more preferably overdamped or critically damped, so as to minimize force oscillations. Fenders are typically manufactured out of rubber, foam elastomer or plastic. Rubber fenders may be either extruded or molded. The type of fender that is most suitable for an application depends on many variables, including dimensions and displacement of the vessel, maximum allowable stand-off, berthing structure, tidal variations and other berth-specific conditions.
While larger vessels such as cargo ships and barges, for example, often have fenders that are essentially immovably affixed or mounted to the vessel, smaller boats, such as pontoon boats and recreational boats, may not have fenders that are securely affixed to the port and/or starboard sides of the boat. Rather, portable fenders must usually be manually placed and positioned along the sides of the boat, as required, when berthing against a dock.
When a boat (e.g., a recreational pontoon boat) is under way, fenders are often stowed or secured on deck in a storage compartment(s), such as under hinged seats, for example. A typical fender for a pontoon boat may be about six to about eight inches in diameter and may be about sixteen to about twenty-four inches in length. A single vessel usually carries multiple (e.g., 2, 4, 8, or any other plurality) fenders at once. Fender storage utilizes sparse vessel storage space that may otherwise be used for other items such as coolers, fishing equipment, towels, clothing or sporting accessories (e.g., life jackets, skis, tubes, etc.), for example.
When preparing for berthing against a dock, a captain and/or crew member(s) must place fender(s) at various locations along the sides of the boat. Attached to the vessel by a line at one end, the fenders may be hung or dangled over the side of the boat. The line (e.g., rope, chain, cable) may be secured to the boat such that the fender hangs down along the side of the boat, preferably radially outward covering a furthest outward portion of the boat, such as a bumper. The fender ultimately contacts the side of the boat on one side of the fender and dock on the other side of the fender, thereby preventing the boat from hitting the dock and/or the dock hitting the boat. Properly placed, the fenders may be placed along the side(s) of the boat prior to reaching the dock. Should the captain be placing the fenders, he or she may have to stop the boat before reaching the dock, place the fenders as required and then proceed to the dock. If the crew is placing the fenders, they may do so, typically at slow speed and within the confines of the harbor, for example, yet still prior to reaching the dock such the fenders are placed before the boat reaches the dock.
Unfortunately, there are variations in dock structures and dock heights with relation to any plurality of vessels or portions (e.g., gunwales) thereof, so fenders must often be placed at varying heights and/or locations about the port sides of the boat depending on the application. While fender placement may be predictable after repeated berthing of the same vessel at the same dock under similar environmental conditions (e.g., wind and water level), placement may be unpredictable with inexperienced captain and/or crew, at unfamiliar dock(s), and/or under varied environmental conditions. Further, when pulling up to a dock, for example, fender position may not be predeterminable because a mooring position may not be visible in time to place fenders properly. Accordingly, duplicative fenders may be required, such that fenders are provide about the perimeter of the boat when fewer fenders could have been employed if a mooring position was determinable. As stated above, fenders are usually aligned sufficiently so that the fender is placed radially outwardly between the boat and the dock thus preventing or minimizing physical contact between the boat and the dock.
As a vessel departs a dock and is underway, fenders may be pulled up from the side(s) of the boat, the lines un-tied and the fenders stored. If the captain is retrieving the fenders, he or she may have to, again, stop the boat and proceed in retrieving and storing the fenders. If the crew is tending to the fenders, this may be done while the boat is under-way and perhaps idling through the marina, for example.
Notwithstanding some disadvantages, prior fenders can be somewhat effective in bodies of water where the water level fluctuates due to tides, surge or rivers, if the dock is a floating dock because as the water level changes, the boat and the dock will rise and fall at the time, thereby causing a particular vertical spacing (e.g., between a horizontal plane including the boat's gunwale and a horizontal plane including a deck of the dock) to remain substantially consistent. Assuming that prior fenders are properly positioned, floating docks may not typically pose a height problem. Floating docks may, however, provide obstacles (e.g., support or safety structures) along their length, thereby complicating fore-aft fender positioning.
Stationary (e.g., non-floating or ground-supported) docking structures may present both vertical and horizontal docking challenges. For example, prior fenders can be somewhat problematic on bodies of water where the water level fluctuates due to tides, surge or rivers, if the dock a non-floating or ground-anchored dock. Where the dock is non-floating, as water levels fluctuate, the boat will rise and fall, but the dock remains at the same height, thereby causing a particular vertical spacing (e.g., between a horizontal plane including the boat's gunwale and a horizontal plane including a deck of the dock) to change due to changing environmental conditions. As the water level rises or falls, prior line-supported fenders will also rise and fall (with the boat) and may therefore not necessarily maintain their “ideal” position between the boat and dock.
Popular prior fenders are pneumatically inflated. Some pneumatic fenders have a fill valve, while others are sealed. An inflated fender is subject to breaking, tearing or otherwise losing its air which may lessen its effectiveness or completely render the fender useless. Should this occur without knowledge (in the middle of the night, for example) the boat may not be properly protected and damage could occur to the boat, the dock or both the boat and dock. Fenders that are inflated but do not have a fill-valve can be affected by temperature variations. For example, a fender that is sufficiently full of air at 80 degrees Fahrenheit may not be sufficiently full of air at 20 degrees Fahrenheit. The false sense of security based on this example may cause the fender to “fail” (e.g., damage to boat, dock, or both) at colder temperatures.
Considering that prior fenders were simply tied to a boat rail, fence or cleat, for example, the fenders may easily be lost or even stolen as there is really no way practical way to attach them to the boat securely. In some applications, these same fenders may be attached to the dock in which case they are used with the same intention of isolating the boat from the dock however, in this case, the fenders are affixed to the dock instead of the boat. In either case, prior fenders whether attached to the dock or the boat, is susceptible to some or perhaps all of the same challenges as described above.